Laboratory experimental study of tire tractive performance on soft soil: Towing mode, traction mode, and multi-pass effect.

• A SRTT tire was tested in traction mode and towing mode on loamy sand. • Test data on tire traction and soil response at slip ratios up to 30% was collected. • Effects of inflation pressure, normal load, and initial soil compaction were analyzed. • Multi-pass effects on tire traction and soil response were discussed. • A new multi-pass effect related to ripple formation and soil failure was discovered. Tire tractive performance, soil behavior under the traffic, and multi-pass effect are among the key topics in the research of vehicle off-road dynamics. As an extension of the study (He et al., 2019a), this paper documents the testing of a tire moving on soft soil in the traction mode or towing mode, with a single pass or multiple passes, and presents the testing results mainly from the aspects of tire tractive performance parameters, soil behavior parameters, and multi-pass effect on these parameters. The influence of tire inflation pressure, initial soil compaction, tire normal load, or the number of passes on the test data has been analyzed; for some of the tests, the analysis was completed statistically. A multi-pass effect phenomenon, different from any phenomenon recorded in the available existing literature, was discovered and related to the ripple formation and soil failure. The research results of this paper can be considered groundwork for tire off-road dynamics and the development of traction controllers for vehicles on soft soil. [ABSTRACT FROM AUTHOR]